Metabolism of Exercising and Resting Human Skeletal Muscle, in the Post-Prandial and Fasting States

1973 ◽  
Vol 44 (5) ◽  
pp. 479-491 ◽  
Author(s):  
Patricia G. B. Baker ◽  
R. F. Mottram
Keyword(s):  
Carbon Dioxide ◽  
Skeletal Muscle ◽  
Oxygen Uptake ◽  
Glucose Uptake ◽  
Maximal Voluntary Contraction ◽  
Human Skeletal Muscle ◽  
Voluntary Contraction ◽  
Contraction Force ◽  
Carbon Dioxide Output

1. Methods are described for study of metabolism of human skeletal muscle in situ, at rest and during mild sustained contraction in the fed and fasted states. 2. At rest the average oxygen uptake was 0.29 ml min−1 100 ml of muscle−1 and the carbon dioxide output was 0.22 ml. Glucose uptake was 0.49 mg min−1 100 ml of muscle−1. The respiratory quotient was 0.75, indicating that most of the glucose was being stored. 3. When subjects made hand-grips of 5% of their maximal voluntary contraction force (5% MVC) the oxygen and carbon dioxide exchanges both increased by six times while the glucose uptake increased by 70% of the resting value. 4. A 7 h fast before the observations were made severely decreased both resting and exercising glucose uptake but produced no other alteration in the metabolism of the muscle.

scholarly journals Repeated contractions alter the geometry of human skeletal muscle

2002 ◽  
Vol 93 (6) ◽  
pp. 2089-2094 ◽  
Author(s):  
Constantinos N. Maganaris ◽  
Vasilios Baltzopoulos ◽  
Anthony J. Sargeant
Keyword(s):  
Skeletal Muscle ◽  
Maximal Voluntary Contraction ◽  
Human Skeletal Muscle ◽  
Voluntary Contraction ◽  
Pennation Angle ◽  
Medial Gastrocnemius ◽  
Myotendinous Junction ◽  
Rest Interval ◽  
In Series ◽  
The Moment

The aim of this study was to investigate the effect of repeated contractions on the geometry of human skeletal muscle. Six men performed two sets ( sets Aand B) of 10 repeated isometric plantarflexion contractions at 80% of the moment generated during plantarflexion maximal voluntary contraction (MVC), with a rest interval of 15 min between sets. By use of ultrasound, the geometry of the medial gastrocnemius (MG) muscle was measured in the contractions of set A and the displacement of the MG tendon origin in the myotendinous junction was measured in the contractions of set B. In the transition from the 1st to the 10th contractions, the fascicular length at 80% of MVC decreased from 34 ± 4 (means ± SD) to 30 ± 3 mm ( P < 0.001), the pennation angle increased from 35 ± 3 to 42 ± 3° ( P < 0.001), the myotendinous junction displacement increased from 5 ± 3 to 10 ± 3 mm ( P < 0.001), and the average fascicular curvature remained constant ( P > 0.05) at ∼4.3 m−1. No changes ( P > 0.05) were found in fascicular length, pennation angle, and myotendinous junction displacement after the fifth contraction. Electrogoniometry showed that the ankle rotated by ∼6.5° during contraction, but no differences ( P > 0.05) were obtained between contractions. The present results show that repeated contractions induce tendon creep, which substantially affects the geometry of the in-series contracting muscles, thus altering their potential for force and joint moment generation.

MRI measures of perfusion-related changes in human skeletal muscle during progressive contractions

2004 ◽  
Vol 97 (6) ◽  
pp. 2385-2394 ◽  
Author(s):  
D. M. Wigmore ◽  
B. M. Damon ◽  
D. M. Pober ◽  
J. A. Kent-Braun
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Maximal Voluntary Contraction ◽  
Human Skeletal Muscle ◽  
Venous Occlusion ◽  
Voluntary Contraction ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Planar Images

Although skeletal muscle perfusion is fundamental to proper muscle function, in vivo measurements are typically limited to those of limb or arterial blood flow, rather than flow within the muscle bed itself. We present a noninvasive functional MRI (fMRI) technique for measuring perfusion-related signal intensity (SI) changes in human skeletal muscle during and after contractions and demonstrate its application to the question of occlusion during a range of contraction intensities. Eight healthy men (aged 20–31 yr) performed a series of isometric ankle dorsiflexor contractions from 10 to 100% maximal voluntary contraction. Axial gradient-echo echo-planar images (repetition time = 500 ms, echo time = 18.6 ms) were acquired continuously before, during, and following each 10-s contraction, with 4.5-min rest between contractions. Average SI in the dorsiflexor muscles was calculated for all 240 images in each contraction series. Postcontraction hyperemia for each force level was determined as peak change in SI after contraction, which was then scaled to that obtained following a 5-min cuff occlusion of the thigh (i.e., maximal hyperemia). A subset of subjects ( n = 4) performed parallel studies using venous occlusion plethysmography to measure limb blood flow. Hyperemia measured by fMRI and plethysmography demonstrated good agreement. Postcontraction hyperemia measured by fMRI scaled with contraction intensity up to ∼60% maximal voluntary contraction. fMRI provides a noninvasive means of quantifying perfusion-related changes during and following skeletal muscle contractions in humans. Temporal changes in perfusion can be observed, as can the heterogeneity of perfusion across the muscle bed.

scholarly journals Effects of Oral Resveratrol Supplementation on Glycogen Replenishment and Mitochondria Biogenesis in Exercised Human Skeletal Muscle

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3721
Author(s):  
Chun-Ching Huang ◽  
Chia-Chen Liu ◽  
Jung-Piao Tsao ◽  
Chin-Lin Hsu ◽  
I-Shiung Cheng
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Muscle Glycogen ◽  
Human Skeletal Muscle ◽  
Young Male ◽  
Gene Expressions ◽  
Plasma Parameters ◽  
Post Exercise ◽  
Glycogen Resynthesis ◽  
Mitochondria Biogenesis

The present study aimed to investigate the effect of oral resveratrol supplementation on the key molecular gene expressions involved in mitochondria biogenesis and glycogen resynthesis in human skeletal muscle. Nine young male athletes participated in the single-blind and crossover designed study. All subjects completed a 4-day resveratrol and placebo supplement in a randomized order while performing a single bout of cycling exercise. Immediately after the exercise challenge, the subjects consumed a carbohydrate (CHO) meal (2 g CHO/Kg body mass) with either resveratrol or placebo capsules. Biopsied muscle samples, blood samples and expired gas samples were obtained at 0 h and 3 h after exercise. The muscle samples were measured for gene transcription factor expression by real-time PCR for glucose uptake and mitochondria biogenesis. Plasma glucose, insulin, glycerol, non-esterified fatty acid concentrations and respiratory exchange ratio were analyzed during post-exercise recovery periods. The results showed that the muscle glycogen concentrations were higher at 3 h than at 0 h; however, there were no difference between resveratrol trial and placebo trial. There were no significantly different concentrations in plasma parameters between the two trials. Similarly, no measured gene expressions were significant between the two trials. The evidence concluded that the 4-day oral resveratrol supplementation did not improve post-exercise muscle glycogen resynthesis and related glucose uptake and mitochondrial biosynthesis gene expression in men.

Does impaired mitochondrial function affect insulin signaling and action in cultured human skeletal muscle cells?

2008 ◽  
Vol 294 (1) ◽  
pp. E97-E102 ◽  
Author(s):  
Audrey E. Brown ◽  
Matthias Elstner ◽  
Stephen J. Yeaman ◽  
Douglass M. Turnbull ◽  
Mark Walker
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Signaling ◽  
Mitochondrial Respiration ◽  
Respiratory Function ◽  
Insulin Action ◽  
Human Skeletal Muscle ◽  
Human Skeletal Muscle Cells ◽  
Basal Glucose Uptake

Insulin-resistant type 2 diabetic patients have been reported to have impaired skeletal muscle mitochondrial respiratory function. A key question is whether decreased mitochondrial respiration contributes directly to the decreased insulin action. To address this, a model of impaired cellular respiratory function was established by incubating human skeletal muscle cell cultures with the mitochondrial inhibitor sodium azide and examining the effects on insulin action. Incubation of human skeletal muscle cells with 50 and 75 μM azide resulted in 48 ± 3% and 56 ± 1% decreases, respectively, in respiration compared with untreated cells mimicking the level of impairment seen in type 2 diabetes. Under conditions of decreased respiratory chain function, insulin-independent (basal) glucose uptake was significantly increased. Basal glucose uptake was 325 ± 39 pmol/min/mg (mean ± SE) in untreated cells. This increased to 669 ± 69 and 823 ± 83 pmol/min/mg in cells treated with 50 and 75 μM azide, respectively (vs. untreated, both P < 0.0001). Azide treatment was also accompanied by an increase in basal glycogen synthesis and phosphorylation of AMP-activated protein kinase. However, there was no decrease in glucose uptake following insulin exposure, and insulin-stimulated phosphorylation of Akt was normal under these conditions. GLUT1 mRNA expression remained unchanged, whereas GLUT4 mRNA expression increased following azide treatment. In conclusion, under conditions of impaired mitochondrial respiration there was no evidence of impaired insulin signaling or glucose uptake following insulin exposure in this model system.

Breathing in brief exercise

1960 ◽  
Vol 15 (4) ◽  
pp. 583-588 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Respiratory Exchange Ratio ◽  
Metabolic Cost ◽  
Carbon Dioxide Tension ◽  
Minute Volume ◽  
Carbon Dioxide Output ◽  
Respiratory Minute Volume ◽  
Before And After

Two men ran for 20 or 60 seconds while inhaling air, oxygen or 4% carbon dioxide. Inspired respiratory minute volume was determined for each breath. Ventilation increased suddenly in the first breath with minimal changes in end-expiratory carbon dioxide tension and respiratory exchange ratio to a rate that remained constant for 20 seconds before increasing further. The rate of carbon dioxide output was uniform during the first 20 seconds. A 12% grade did not increase ventilation or oxygen uptake during runs of 20 seconds, but in the first minute of recovery, ventilation was 64% greater than after level runs. Inhalation of oxygen inhibited ventilation by 24% in the 20-second periods before and after the end of a 60-second run. Inhalation of carbon dioxide begun at rest produced increments in ventilation and end-expiratory carbon dioxide tension that varied little during running and recovery. In the 20-second runs ventilation varied with speed but appeared independent of ultimate metabolic cost. Submitted on January 21, 1960

Use of respiratory quotients in assessment of aerobic work capacity

1962 ◽  
Vol 17 (1) ◽  
pp. 47-50 ◽  
Author(s):  
B. Issekutz ◽  
N. C. Birkhead ◽  
K. Rodahl
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Carbon Dioxide Output ◽  
Ergometer Test ◽  
Aerobic Work Capacity ◽  
Bicycle Ergometer Test ◽  
Better Than

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.

Thermogenic response to epinephrine in the forearm and abdominal subcutaneous adipose tissue

1992 ◽  
Vol 263 (5) ◽  
pp. E850-E855 ◽  
Author(s):  
L. Simonsen ◽  
J. Bulow ◽  
J. Madsen ◽  
N. J. Christensen
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Glucose Uptake ◽  
Subcutaneous Adipose Tissue ◽  
Whole Body ◽  
Epinephrine Infusion ◽  
Basal Period ◽  
Subcutaneous Adipose

Whole body energy expenditure, thermogenic and metabolic changes in the forearm, and intercellular glucose concentrations in subcutaneous adipose tissue on the abdomen determined by microdialysis were measured during epinephrine infusion in healthy subjects. After a control period, epinephrine was infused at rates of 0.2 and 0.4 nmol.kg-1 x min-1. Whole body resting energy expenditure was 4.36 +/- 0.56 (SD) kJ/min. Energy expenditure increased to 5.14 +/- 0.74 and 5.46 +/- 0.79 kJ/min, respectively (P < 0.001), during the epinephrine infusions. Respiratory exchange ratio was 0.80 +/- 0.04 in the resting state and did not change. Local forearm oxygen uptake was 3.9 +/- 1.3 mumol.100 g-1 x min-1 in the basal period. During epinephrine infusion, it increased to 5.8 +/- 2.1 (P < 0.03) and 7.5 +/- 2.3 mumol.100 g-1 x min-1 (P < 0.001). Local forearm glucose uptake was 0.160 +/- 0.105 mumol.100 g-1 x min-1 and increased to 0.586 +/- 0.445 and 0.760 +/- 0.534 mumol.100 g-1 x min-1 (P < 0.025). The intercellular glucose concentration in the subcutaneous adipose tissue on the abdomen was equal to the arterial concentration in the basal period but did not increase as much during infusion of epinephrine, indicating glucose uptake in adipose tissue in this condition. If it is assumed that forearm skeletal muscle is representative for the average skeletal muscle, it can be calculated that on average 40% of the enhanced whole body oxygen uptake induced by infusion of epinephrine is taking place in skeletal muscle. It is proposed that adipose tissue may contribute to epinephrine-induced thermogenesis.

scholarly journals The effect of graded exercise on IL‐6 release and glucose uptake in human skeletal muscle

2003 ◽  
Vol 546 (1) ◽  
pp. 299-305 ◽  
Author(s):  
Jørn W. Helge ◽  
Bente Stallknecht ◽  
Bente Klarlund Pedersen ◽  
Henrik Galbo ◽  
Bente Kiens ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Human Skeletal Muscle ◽  
Graded Exercise
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